The invention relates to a manually operable can opener which has a rotatable traction wheel and a rotatable cutter blade for lateral engagement with the rim or side wall of a metal can in order to cut open the can.
Manually operable can openers have been known for many years and may be broadly categorised into three types: a first type having a cutter blade which cuts directly into the top wall of a can, a second type having a cutter blade which cuts into the side wall of the can below the rim, and a third type having a cutter blade which cuts partially into the rim of the can.
In the first type of can openers, the cutter blade has a rotational axis inclined to that of the traction wheel. The traction wheel and cutter blade are usually provided with respective circular gears in mesh with each other in use, whereby rotation of the traction wheel by the user in one direction causes rotation of the cutter blade in the opposite direction. In operation, the traction wheel engages the rim of a can from below, extending substantially parallel to the central or rotational axis of the can. The cutter blade penetrates completely through and cuts into the top wall of the can at a position slightly radially inwards of the rim, whereby the top wall is removable upon a complete revolution of the can about its central axis relative to the can opener. A disadvantage of this type of can openers is that metal cuttings and/or other contaminants on the outer surface of the top wall may fall into the can during opening. The cut away top wall is also difficult to remove as it may fall into the can.
Can openers of the second type have a traction wheel and a cuter blade whose axes of rotation are substantially parallel to each other, in that the wheel and the blade overlie one another to some extent when the can opener is in its operative condition. The traction wheel is rotatable by the user and the cutter blade is freely rotatable. In use, the traction wheel engages the radially inner surface of the rim of a can, with its axis of rotation substantially parallel to the central axis of the can. The cutter blade laterally penetrates completely through and cuts into the side wall of the can at a position slightly below the rim, whereby the top wall including the rim of the can are removable together upon a complete revolution of the can about its central axis relative to the can opener.
A can opener of the third type has been disclosed in UK Patent No. 2334939, which has a cutter blade so disposed relative to the traction wheel that in use, the cutter blade cuts into but not completely through the rim of the can. Cans are generally formed from a cylindrical metal body and two separate metal end walls, in that each end of the body and the outer edge of a respective end wall are folded together to form a sealed closure rim. The rim has five layers of metal when viewed in cross section, being a radially inner, a radially outer and a central layer of the end wall metal, and two intermediate layers of the body metal interlaced with the three layers of the end wall metal. A can opener incorporating a rim-cutting mechanism of this type is operable to cut laterally through the outermost layer of the rim. This results in the remainder of the end wall becoming releasable from the can body, thereby leaving a part of the rim in situ on the end wall and the other part of the rim in situ on the can body.
The present invention is directed to the second and third types of can openers, or collectively referred to as a laterally-cutting type, which at present are uncomfortable to use and especially awkward for left-handed users.
It is an object of the invention to overcome or at least reduce such problems.
According to a first aspect of the invention, there is provided a can opener of the laterally-cutting type, comprising a pair of operating members pivotal with respect to each other, one said member mounting a rotatable traction wheel and the other said member a rotatable cutter blade. The wheel and blade are movable between an inoperative position in which the wheel and the blade are spaced apart to an extent that the rim of a can to be opened is locatable between the wheel and the blade, and an operative position in which the wheel and the blade are in close proximity and engageable with the can to effect opening thereof, in which the traction wheel and the cutter blade have respective rotational axes which in use are substantially parallel to a central axis of the can. The can opener includes a housing formed on said one member, an operating element provided on one side of the can opener and supported by the housing and arranged to rotate about an axis generally transverse to the central axis of the can, and gearing provided in the housing mechanically coupling the operating element to the traction wheel.
Preferably, the gearing comprises two bevel gears.
For convenience of operation, the gearing is arranged to provide a mechanical advantage for the operating element.
It is preferred that the operating element is in the form of a butterfly knob.
In a preferred embodiment, the rotational axis of the operating element is inclined upwards at an angle in the range of 0xc2x0 to 45xc2x0 with respect to the plane of rotation of the traction wheel.
Specifically, the can opener is one of the third type as hereinafter defined.
According to a second aspect of the invention, there is provided a can opener of the laterally-cutting type, comprising a pair of operating members pivotal with respect to each other in use about a substantially vertical axis, one said member mounting a rotatable traction wheel and the other said member mounting a rotatable cutter blade. The wheel and the blade are movable between an inoperative position in which the wheel and the blade are spaced apart to an extent that the rim of a can to be opened is locatable between the wheel and the blade, and an operative position in which the wheel and the blade are in close proximity and engageable with the can to effect opening thereof. The can opener includes a housing formed on said one member, an operating element provided on one side of the can opener and supported by the housing and arranged to rotate about an axis generally transverse to the central axis of the can when the opener is in use on the can, and gearing provided in the housing mechanically coupling the operating element to the traction wheel.
Preferably, the gearing comprises two bevel gears.
For convenience of operation, the gearing is arranged to provide a mechanical advantage for the operating element.
It is preferred that the operating element is in the form of a butterfly knob.
In a preferred embodiment, the rotational axis of the operating element is inclined upwards at an angle in the range of 0xc2x0 to 45xc2x0 with respect to the plane of rotation of the traction wheel.
Specifically, the can opener is one of the third type as hereinafter defined.
According to a third aspect of the invention, there is provided a can opener of the laterally-cutting type, comprising a pair of operating members pivotal with respect to each other in use about a substantially vertical axis, one said member mounting a rotatable traction wheel and the other said member mounting a rotatable cutter blade. The wheel and the blade are movable between an inoperative position in which the wheel and the blade are spaced apart to an extent that the rim of a can to be opened is locatable between the wheel and the blade, and an operative position in which the wheel and the blade are in close proximity and engageable with the can to effect opening thereof. The can opener includes a housing formed on said one member, and an operating element provided on one side of the can opener and supported by the housing for rotating the traction wheel. Said one side of the opener is the left side to a user when the opener is used on the can by the user. The element is rotatable about an axis extending at an angle in the range of 45xc2x0 to 90xc2x0 downwards from the rotational axis of the traction wheel.
Preferably, the can opener further includes gearing provided in the housing mechanically coupling the operating element to the traction wheel.
More preferably, the gearing comprises two bevel gears.
For convenience of operation, the gearing is arranged to provide a mechanical advantage for the operating element.